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Implants in orthodontics / fixed orthodontic courses


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Implants in orthodontics / fixed orthodontic courses

  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education
  3. 3.  Introduction  Classification of Implants  Materials used for Implants  Osseointegration  Use of Implants in Orthodontics
  4. 4. .  Implants are defined as alloplastic devices which are surgically inserted into or onto the jaw bone-Boucher  Linkow- Father of oral Implantology.
  5. 5. Classification of Implants. Based on their location: Subperiosteal  Transosseous  Endosseous
  6. 6.  Based on their configuration:- Root form Implants (Threaded or non threaded) - Blade/Plate Implants (Porous or nonporous).
  7. 7.  Based on the biologic adaptation at the interface:-Implants which osseointegrate. -Implants which do not osseointegrate.  Based on the loading characteristics :-Nonlatency implants. -Latency implants.
  8. 8.  Based on anchorage requirement:-Direct anchorage. -Indirect anchorage.  According to composition:-Stainless steel -Cobalt-Chromium-Molybdenum (Co-Cr-Mo) -Titanium -Ceramics.
  9. 9.  Stainless steel:-18% Cr & 8% Ni. -subjected to crevice & pitting corrosion.  Cobalt-Chromium-Molybdenum Alloy :-used in fabrication of custom designs such as subperiosteal frames.
  10. 10.  Titanium:-most widely used metal for implants. -Highly reactive & readily oxidises to form oxide. -exist in 3 forms -Alpha -Beta -Alpha-Beta phase (most commonly used). Ti-6Al-4V
  11. 11.  Ceramics:- two types Bioactive-Hydroxyapatite Bioglass- contain oxides of Ca, Na, P & Si.  Miscellaneous:-Vitreous carbon, Vitallium, Tantalum, Platinum, Tungsten, Alumina, Polymers & composites.
  12. 12. Materials used for Implants  In 16 &17th century –Ivory dental implants .  20th century-Metal Implant devices.  1940 &1960’s-CoCrMo subperiosteal & titanium blade implants.
  13. 13.  1970’s-Non metal biomaterials  1982-Branemark Implant.
  14. 14. Biocompatibility of Titanium Implants.  “Passivity”.  Modulus of elasticity .
  15. 15. Biocompatibility of Titanium Implants: Titanium can be considered as composite material.  Chemical process at the Interface: Types of bonding by which biomolecules stick to the Implant surface are -Long range but weak van der waals interaction. -Short range, strong chemical bonding. e.g.:-ionic & covalent bonds.
  16. 16. Chemical process that take place at an Implant-Biotissue interface.
  17. 17. Studies regarding the stability of the Implant materials.  Gainesforth & Higley (1945): -investigated the efficacy of Vitallium screw for orthodontic anchorage. -Screws were inserted into the ramus of 6 dogs and immediately loaded to retract the maxillary cuspids. -Results:-All the screws were lost within 16 to 31 days.
  18. 18.  Sherman(1978):- - Inserted Vitreous carbon implants in 6 dogs & allowed to heal for 70 days before applying a force of 175gms. Results:-After 2wks only two implants were stable.  Smith(1979):- Investigated bioglass- coated aluminum oxide implants that were allowed to heal for 12wks before loading them with 425gms of force for 2-9wks. Results:- All the Implants remained stable except for a slight movement when the force was doubled.
  19. 19.  Gray(1983):-Tested the bioglass implants & vitallium implants which were placed in femur of rabbits. After 28 days healing period, loads of 60,120,&180gms were applied. Results:-No movement of the implants occurred. Eugene Roberts(1984):Inserted pure titanium screws shaped implants into the femurs of rabbits & after a healing period of 6-12wks, the paired implants were loaded with 100gms of force for 12 wks. Results:-Histologically increase in the bone mass in the area of loaded implant was seen.
  20. 20.  Eugene Roberts(1988):Examined histologic sections of dog mandibles containing rigid titanium screws to compare the findings of bright field & polarized light microscopic illumination to microradiographs of mineralized sections. Results:-10% direct bone contact is sufficient to resist the implant movement.  Linder-Aronson(1990):-tested the effectiveness of Branemark implants in monkeys.
  21. 21. OSSEOINTEGRATION.  Term & concept of Osseointegration -Branemark. “An intimate structural contact at the implant surface and adjacent vital bone devoid of any intervening fibrous tissue.”
  22. 22. Evolution of the concept of osseointegration  Vital microscopic studies of the rabbit fibulatitanium chambered microscopes.  Series of experiments:-Titanium fixtures for immobilization of autologous bone grafts. - Tooth implants studies for healing & anchorage stability.
  23. 23.  Study done on dogs to find out the load bearing capacity of implants.  Optical titanium chambers were implanted in humans-to assess the tissue reactions of titanium implants.
  24. 24. Biology of osseointegration. Hematoma Callus formation
  25. 25. Bone remodeling Fibrous tissue
  26. 26. Principles of osseointegration Factors important for reliable bone anchorage of an Implanted device:Implant biocompatibility:-
  27. 27. Principles of osseointegration.  Implant Design:-
  28. 28.  Implant surface:-
  29. 29.  State of the host bed:-
  30. 30.  Surgical technique:-
  31. 31.  Loading condition:-
  32. 32. Use of Implants in Orthodontics  Growth Studies  Anchorage Orthopaedic -Expansion -Protraction Orthodontic -Intrusion -Space closure -Molar Distalization.
  33. 33. Growth Studies:-  Implants are the best means of reference points for studying the longitudinal growth studies.
  34. 34.  Growth Rotations -Bjork & skeiller .  Growth of Cleft lip & palate patients - Shaw .
  35. 35. ANCHORAGE: Orthopeadic correction- Two methods for obtaining the Skeletal anchorage: Intentionally Ankylosed teeth.  Endosseous Implants.
  36. 36.  Maxillary Expansion:- - Guyman(1980) -Ankylosed teeth acted as abutments for palatal expansion in rhesus monkeys. -Transmit the laterally directed forces across the midpalatal suture.
  37. 37. • After 8wk healing period 1-2 pound force was applied to the ankylosed teeth. • Palatal widening was seen due to skeletal expansion that was periodically assessed during 13, 21, & 23 wks.
  38. 38. Frontonasal suture expansion using titanium screws. -Kiumars Movassaghi et al(1995) Pure titanium craniofacial plates were contoured into ‘L’ shape with a 90 degree angle at the midpoint. Plates were placed on either sides of the suture. A distraction force of 55gms was activated across the sutures.
  39. 39. Increase in growth about 6mm was seen across the frontonasal suture.
  40. 40. Sutural expansion using rigidly integrated endosseous implants. Andrew Parr et al(1996) Evaluated the use of endosseous implants in the midface region,2 flanged titanium implants were placed on either side of the midnasal suture of rabbits. Divided into two groups: one group-1N & other group-3N force was applied. .
  41. 41.  An open coil spring has been compressed between the abutments to provide the expansion load.  Distance between the implants increased significantly in the loaded groups & higher in the 3N group.
  42. 42. Endosseous Implants for maxillary protraction -Smalley etal (1988) Tantalum markers were placed in the cranial base, mandible, zygomatico Temporal , zygomaticomaxillary, frontomaxillary, premaxillomaxillary Sutures.
  43. 43. •A traction force of 600gm is used and protraction was done till 8mm of anterior displacement of maxillary complex occurred.
  44. 44. Implants for Intrusion Skeletal Anchorage :-Creekmore(1983) -Vitallium bone screw placed below the anterior nasal spine is used for intrusion of Upper anteriors. -6mm of upper incisor intrusion was seen after one year.
  45. 45. Implants for space closure.  Implanto-Orthodontics-Linkow.(1970).  Implant was used to replace the missing tooth.  Upper arch was consolidated using a fixed appliance & in lower arch only premolar and molar were banded and connected by o.o4o rigid Elastic wire.
  46. 46. Use of Endosseous Implant for closure of extraction-Eugene Roberts (1989) site  Endosseous Implants placed in the retromolar region are used to close the atrophic extraction site. Pontic
  47. 47.
  48. 48. Buccal view after mesial translation of 2nd & 3rd molars.
  49. 49. Diagnostic models,2.5yrs Of post retention.
  50. 50. Onplant & Ortho-Implant.  Onplant:-Block &Hoffman.(1995)  It is a flat disk shaped fixture available in 8 and 10mm in diameter  It has a HA coated surface for integration with the surrounding bone.
  51. 51. Animal studies: In the dog, the onplant has been exposed & connected to the contra lateral 2nd premolar with a stainless steel spring activated to deliver 110z of force . 5months later tooth moved towards the onplant by 8mm from its original position.
  52. 52. An expansion device soldered to a traspalatal bar & secured to the expansion device to control molar distalization. The 2nd molars were bodily distalized 6mm in 11 months.
  53. 53.
  54. 54.
  55. 55. Ortho-Implant - Celenza & Hochman •Similar to onplant but it is an endosseous Implant. •Its surface is sandblasted and etched to increase the adhesion to the surrounding bone
  56. 56.
  57. 57. Uses of Onplant & Ortho-Implant  Space closure.  Molar distalization.
  58. 58. Palatal Bone Support for placement of an Orthodontic Implant is sufficient enough without causing any damage to the Nasal floor. -Heinrich et al (1999)
  59. 59. Impacted Titanium Post for Anchorage -Frederic Bousquet etal(1996) •35-yr old female before treatment, showing anterior crowding.
  60. 60. Titanium post Titanium post & head of Mechanical impactor.
  61. 61. Post impacted in interdental septum between 1st molar & extraction site. Rigid .040 wire connecting 1st molar tube to post.
  62. 62.
  63. 63. Upper right posterior segment after 2 months of retraction showing distal movement of Premolar & no mesial movement of molar.
  64. 64. Cast models after 18 months of treatment.
  65. 65. Mini-Implant for Orthodontic Anchorage:-Ryuzo Kanomi(1997)  Mini-Implant is 1.2mm in diameter and 6mm in length.
  66. 66. After raising of mucoperiosteal flap and denuding of bone, 2mm of round bur is used. Pilot drill used to enter bone same Distance as the length of mini-implant. Mini-Implant inserted with accompanying screw driver.
  67. 67. Mucosal punch used to remove soft-tissue Surrounding head of mini-implant. Two hole titanium bone plate attached to head of mini-implant and tied to bracket with ligature wire.
  68. 68. Patient at start of incisor intrusion.
  69. 69. Mini-Implants for space closure.
  70. 70. Mini-Implants for molar intrusion
  71. 71. Skeletal Anchorage system for Open bite correction -Umemori , Sugawara etal (1999) • Control of vertical dimension is very important in correction of anterior open bite •‘L’ shaped titanium miniplates are used as a Source of anchorage for intruding the molars.
  72. 72.  Procedure for miniplate insertion:-
  73. 73.
  74. 74. Pretreatment facial photographs Pretreatment intraoral photographs
  75. 75. Post treatment intraoral photographs
  76. 76. ‘Y’ Titanium miniplate for intrusion & distalization of maxillary molars. (key ridge) Straight titanium miniplate for Intrusion of maxillary incisors. (anterior ridge of piriform opening).
  77. 77. Intrusion of maxillary anterior teeth using SAS Before treatment Intrusion of maxillary anteriors After treatment
  78. 78. Microimplant (Absoanchor) Kyung, Park et al Recent among the implants – Microimplant. To overcome disadvantages of conventional Osseointegrated implants like -size, procedure of insertion, cost, & bulkiness. Diameter is 1.2mm but available in different sizes.
  79. 79.
  80. 80. Usually 4-5mm length of implant with 1.2-1.3mm diameter will provide adequate retention, but in maxilla a microimplant of 6-8mm is used. Microimplant insertion:-
  81. 81. Periapical radiograph to see the root approximation. • NiTi coil spring applied to maxillary buccal & lingual and mandibular buccal microimplants.
  82. 82. Micro Implant -Park et al  Dimension of micro implant are 1.2mm in diameter & 6mm in length. 28yr old female with CL-I bialveolar protrusion before treatment.
  83. 83. Placed in the buccal alveolar bone between 2nd premolar &1st molar in the upper arch & between 1st molar & 2nd molar in the lower arch. Placement of maxillary microscrew. Mandibular microscrew.
  84. 84. Initial maxillary canine retraction force applied with tieback between micro-implant & canine. After 2 months of treatment, maxillary anterior retraction force applied with nickel titanium coil spring.
  85. 85. Mandibular micro-implants between 1st & 2nd molars. Force applied with elastic thread between microscrews & mandibular archwire.
  86. 86. Mechanism of bodily retraction of anterior segment, with force applied against microimplant passing near center of resistance of six anterior teeth. Mandibular microimplant uprights & intrudes the molars.
  87. 87. . Patient after 18 months of treatment
  88. 88. Superimposition of pre & post- treatment cephalometric tracings.
  89. 89. Micro-Implant for anchorage in Lingual orthodontics 19yr old female with skeletal CL-II malocclusion before treatment.
  90. 90. Palatal microscrew should be implanted into the alveolar bone at 30-40 degree between 1st & 2nd molar to avoid root damage.
  91. 91. Lingual Sliding mechanics using nickel titanium coil springs to microimplants.
  92. 92. Patient after 16 months of treatment.
  93. 93. Superimpositions of cephalometric tracings before & after treatment.
  94. 94. 28yr old female CL-II patient with lip protrusion & gummy smile before treatment.
  95. 95. Insertion site measured from guide bar on bite-wing x-ray Stab incision for flap reflection Drilling through cortical bone only. Microimplant insertion.
  96. 96. Maxillary .017x.o25 ss closing loop archwire & .016x.016ss overlay intrusion archwire used to retract anterior teeth upward & backward.
  97. 97. Schematic of retraction wire.
  98. 98. Improvement in profile & gummy smile after treatment.
  99. 99. Use of Osseointegrated Implants in unilateral cleft lip & palate pts. Hiroaki et al (1999)  Unilateral cleft pts who needed maxillary lateral bony defect in the alveolar region restricts orthodontic accomplishment.  Late secondary bone grafting to the cleft region followed by the insertion of the Osseointegrated implants provides good retention to the maxillary arch.
  100. 100. Bibliography.     Implants in dentistry-Hobkirk. Block & Kent- Oral Implantology. Science of dental materials- Skinner. Orthodontic principles & practice-Graber & Vanarsdall.
  101. 101.  Bone responses to orthodontic forces on vitreous carbon dental implants –Alan Sherman AJO:JULY 78.  Bone dynamics associated with the controlled loading of bioglass coated aluminum oxide endosteal implants-John Smith AJO:DEC 79.  Ankylosed teeth as abutments for palatal expansion in rhesus monkeys. Guyman et al AJO :sep 83.  Osseous adaptation to continuous loading of rigid endosseous implants. AJO :AUG 84.  Osseointegrated titanium implants for maxillofacial protraction-Smalley et al AJO:OCT 88.
  102. 102.  Implant-Orthodontics-Linkow JCO MAY 70.  Possibility of skeletal anchorage- Creekmore JCO APR 83.  Absolute anchorage device-Hoffman & block AJO MAR 95.  Rigid implant anchorage to close a mandibular first molar extraction site –Roberts et al JCO:DEC 94.  Osseointegration and its experimental background.J.Prosth. dent sep 83.  Biocompatibility of titanium implants –kasemo. J.Prosth.dent jun 83.  Endosseous implants as anchorage to protract molars and close an atrophic extraction site.-Roberts, Marshall AO sep 89.
  103. 103.  Frontonasal suture expansion in rabbits using titanium screws.-Movassaghi et al J. of oral max. surg 95.  Sutural expansion in using endosseous implants –Rabbit study-Parr AO may 96.  Use of impacted titanium post for orthodontic anchorage – Bousquet et al JCO AUG 96.  Mini-Implant-Ryuzo kanomi. JCO 97.  Skeletal Anchorage System-Sugawara JCO DEC 99.
  104. 104.  Micro-Implant anchorage for treatment of skeletal class-I Bialveolar protrusion-Hyo-Sang Park.2001 JUL JCO.
  106. 106.  Introduction  Types of magnetic materials  Properties of magnets  Application of magnets in orthodontics.
  107. 107.  In 1953, magnets were first used for denture retention by BEHRAN & EGAN.  Use of magnets in orthodontic- BLECHMAN & SMILEY.
  108. 108. PROPERTIES OF MAGNETS  Flux Density
  109. 109.  In dentistry, ferromagnetic materials with static field are used.  Magnetocrystalline Anisotropy.  Coercivity.
  110. 110.  Coulombs law:-This law states that force between two magnetic poles is directly proportional to magnitude & inversely proportional to square of the distance between them.  Curie point:-Pierre Curie(1859-1906)
  111. 111.  High force to volume ratio.  Maximal force at shorter distances.
  112. 112.  No interruption of magnetic force lines by intermediate media.  No energy loss.
  113. 113. TYPES OF MAGNETIC MATERIALS       Platinum-cobalt (Pt-co) Aluminium-Nickel-Cobalt(Al-Ni-Co) Ferrite Chromium-cobalt-Iron Samarium Cobalt(SmCo) Neodymium-Iron-Boron(Nd2Fe B) 14
  114. 114.  Advantages:-Continuous force is exerted. - Eliminates the patient co-operation. -No friction.  Disadvantages:-Tarnish & corrosion products are cytotoxic. -Cost factor.
  115. 115.  Biological effect of magnetic forces:- Aronson:-thinning of epithelium under attracting & repelling magnets. McDonald - proliferative activity of fibroblasts in presence of static magnetic field Lars Bondemark & Kurol studied changes in human dental pulp and gingival tissue.
  116. 116. Clinical Applications of Magnets. Orthopaedic - Expansion -Growth modulation Orthodontic -Tooth Intrusion -Space closure -Molar Distalization. -Retainer.
  117. 117.  EXPANSION:-Vardimon et al(1987) demonstrated palatal expansion using two types of magnetic devices in Macaca fascicularis monkeys. -Tooth borne appliance
  118. 118.  Tissue borne appliance (attached directly to palate by endosseous pins).
  119. 119. Change in the Inter incisal relationship Maxillary Protraction was related to A-P activity of the premaxillary suture (primarily) & the transverse palatine suture (secondarily).
  120. 120. Transverse change as measured from before and after treatment models. Intercanine change vs. Intermolar change
  121. 121.  Functional Orthopaedic Magnetic Appliances:Vardimon(1989) -for correction of CL-II
  122. 122.
  123. 123. 4 types of functional magnetic system:-
  124. 124.
  125. 125.  Magnetic Twin Block:Clark(1996) -Samarium cobalt magnets were embedded in the inclined surface of the twin block in attractive mode.
  126. 126.  Magnetic Activator Device(MAD):-Darendilier (1993) developed this magnetically active functional appliance. -MAD I-mandibular deviations -MAD II-CLII malocclusion -MADIII-CLIII malocclusion -MADIV-skeletal open bite correction.
  127. 127. MAD-II MAD II is used for correction of CL-II malocclusion. It consists of upper& lower removable appliance , carrying magnets in both buccal segments.
  128. 128. A 30 degree inclination of the occlusal surface of the magnet to the basal surface produces an oblique force vector to correct a CL-II malocclusion.
  129. 129. Mechanical retention of the appliance against the magnetic forces is by clasps on the posterior teeth & in the anterior area by adding small amount of composite on the labial surface so that the labial bow rests on it.
  130. 130. • A 10yr old pt with a skeletal & dental CL-II Div 1 malocclusion. Overjet-6mm & Overbite-3mm.
  131. 131. After 4 months of night time wear
  133. 133. MAD II appliance with transverse screw & two sagittal screws incorporated in lingual side of the lower appliance to permit the sagittal reactivation.
  134. 134. Early CL-III treatment with Magnetic appliance. Patient before treatment.
  135. 135. Combined MED & MAD III appliance  MAD III Bonded upper plate ,with two midpalatal Samarium cobalt magnets. Removable lower plate with buccal magnets.
  136. 136.
  137. 137. Patient after 14 months of treatment.
  138. 138.  MAD - IV Magnetic activator device IV uses anterior attracting & posterior repelling magnets.
  139. 139. •MAD IV consists of removable upper & lower plates each of which contains three cylindrical neodymium magnets coated with stainless steel.
  140. 140. MAD IV(a) MAD IV( b) MAD IV( c)
  141. 141.  Tooth Intrusion:Active Vertical Corrector-Dellinger(1986) -Samarium cobalt magnets in the repelling mode are used.
  142. 142.
  143. 143. Pre-Treatment Post-Treatment
  144. 144.  Fixed Magnetic Appliance:-introduced by VARUN KALRA & CHARLES BURSTONE. Appliance consists of an upper &lower acrylic splints with samarium cobalt magnets in stainless steel casting embedded in a repelling mode.
  145. 145. Results:-Length of the mandibular condyle increased significantly in the treated group. -the entire upper and lower arches intruded during the treatment.
  146. 146.  Tooth Impaction:- Vardimon,Graber,Drescher -Neodymium Iron Boron magnets can be used to assist eruption of an impacted canine.
  147. 147. Vertical &Horizontal magnetic brackets were designed with the magnetic axis magnetized parallel and perpendicular to the base of the edge wise bracket. •Vertical type –Impacted canines & incisors . •Horizontal type –Impacted premolars &molars.
  148. 148. Surgical procedure:Palatal approach was used to expose the maxillary canine. Vertical magnetic bracket bonded on the palatal crown surface of the impacted canine.
  149. 149. • A spacer of 2.5mm is positioned between the magnetic bracket & loose intraoral magnet. •Fixation of the intraoral magnet to the Hawley type retainer with self curing acrylic followed by removal of spacer , to apply an attraction force of 0.3N.
  150. 150. •Treatment progression of the magnetic attraction after 3 months. • Fixed appliance treatment stage.
  151. 151. An attractive solution to unerupted tooth. -Sandler(1991)
  152. 152. •Upper left canine erupting through the mucosa. •Larger magnet repositioned to allow further movement. •Sufficient eruption to allow attachment to be placed.
  153. 153. Detailing with fixed Appliance. Post -treatment Mancini(1996)-force levels are sufficient enough to induce the cellular & biochemical changes required to produce orthodontic tooth movement.
  154. 154. space closure:-Complex Intra & Interarch Mechanics:-Blechman(1985) CL-II mechanics with a magnetic force system in a CL-I extraction case
  155. 155. 3 magnet configuration to enhance CL-II mechanics 3 magnet configuration used to simultaneously move all 4 canines distally
  156. 156. Intramaxillary magnetic force to move Canine distally.
  157. 157. Upper canine retraction Pre-treatment. Lower canine retraction Post-treatment
  158. 158.  Molar Distalization:-Gianelly et al(1989):-repelling magnets in conjunction with a modified Nance appliance was used. Lateral view of magnets in position.
  159. 159. -A 11yr/F with a CL-II DIV I malocclusion in the late mixed dentition period. -Nance appliance was seated on the second deciduous molar. Results:-Molar movement in distal direction-3.2mm Deciduous molar movement in mesial direction-0.6mm
  160. 160. Molar distalization with repelling magnets -Takami etal(1991) The Molar distalization system uses two opposing magnets for each maxillary quadrant. . • Nance appliance is placed to reinforce the anchorage. • Constant magnetic force of 80z is applied. • Magnets are reactivated for every 2wks
  161. 161. Case from the present study before & after rapid molar distalization.
  162. 162. Repelling magnets vs. superelastic Ni-Ti coils. Bondemark & Kurol (1992).  In simultaneous distal movement of maxillary first & second molars -Mean distal movement for supercoils is 3.2mm. -for magnets is 2.2mm.
  163. 163.  Magnetic Edgewise Brackets:-Kawata(1987) -Samarium cobalt magnet with an edgewise bracket (o.018slot) .
  164. 164. Clinical application of magnetic brackets in crowded dental arch. Cast models before & after treatment.
  165. 165. Autonomous fixed magnetic appliance. -Darendeliler & Joho  Treatment of CL-II bimaxillary protrusion with magnets:. A13yr old female patient before treatment
  166. 166. •Ideal arch form using Bonwill-Hawleys method. •Calculation of mesial & distal magnet cuts needed to create proper arch form. •Upper & lower magnetic arches before coating.
  167. 167. Lower magnets temporarily affixed to cast for Indirect bonding.
  168. 168. Magnetic arches in place.
  169. 169. Additional magnet bonded to close median diastema Patient after 6 months of treatment with AFA
  170. 170.  Propellant Unilateral Magnetic Appliance (PUMA) - Chate(1995)  Magnets are use to stimulate costo-chondral bone graft in Hemi facial microsomia.
  171. 171.  Retainers:-Springate & Sandler(1991) -micro magnets made of neodymium iron boron magnets as a fixed retainer in a patient with persistent diastema.
  172. 172.  Bibliography:- -Dentofacial Orthopedics with functional appliances-T.M Graber, Rakosi,Petrovic. -Magnetic force systems in orthodontics-Blechman AJO 78. -Rare earth magnets and Impaction-Vardimon AJO 91. -Use of magnets to move the molars distally-Gainelly AJO 89. -Magnetic vs Mechanical expansion with different thresholds and points of force application. Vardimon.AJO 87. -Effects of fixed magnetic appliance on the dentofacial complex. Kalra.AJO 89. -A new orthodontic force system of magnetic brackets. Kawata AJO 87. -An open bite correction with MAD IV. JCO 95. Darendeliler.
  173. 173. Thank you Leader in continuing dental education